Control mechanism for hydraulic devices



Dec. 3, 1935. R, ERLING I YCONTROL MEGHANsM FOR HYDRAULIC DEVICES AFiled Aprilvle, 1954- 2 sheets-sheet 1 )Trrl 1 lll/1 ATTOR EY Dec. 3,1935. R. ERLING CONTROL MECHANISM FQR HYDRAULIC DEVICES Filed April 16,1954 2 Sheets-Shea?, 2

INVENTOR RALPH ERL l N G ATTQRNEY Patented Dec. 3, 1935 UNITED STATESPATENTv GFFICE CONTROL MEonANisM Fon HYDRAULIC nEvIcEs I l Ralph Erling,Alexandria, Va. Application April 16, 1934, Serial No. 720,840 7 Claims.(Cl. 60-52) (Filed but not issued In the drawings:

Fig. 1 illustrates one form of the present invention, the pump beingshown in section along the axis of rotation thereof;

Fig. 2 is a section through the pump transverse to its axis of rotation;

Fig. 3 is an enlarged detail view of one of the adjustable connectingmeans;

Fig. 4 shows a hydraulic system wherein is included another form of myinvention;

Fig. 5 is a detail view of to the pump controls;

Figs. 6 and 7 are fragmentary plan views showing the interrupted gear intwo different positions;

Fig. 8 is a sectional elevation through Fig. 7 on line 8 8.

The invention forming the subject of the present. app ication 1s 1n manyrespects similar to the device disclosed piston type of variabledelivery pump, and another form in connection with an axial piston pump,equally satisfactory results will be had from either control apparatusif used with either type of pump.

The rudder post 9 is connected by means of tiller l0 to ram l l whichthas its opposite ends disposed to operate as pistons in cylinders l2and i3 that are respectively connected to pump i4 by under the act ofMarch 83, as amended April 3 pipes l5 and I6. Manually operable wheel I1is connected to sun pinion I8 of diierential gear i9 by worm 20, gearv2| and shaft 22. The planet on rotatable shaft 29 and has at its otherend 1.0 teeth 30 that may be meshed with teeth 21 on the differentialmember, the stops 3| being provided to limit the swing of sector 28. Aroller 32 is rorides up on the edge of flange 26 and prevents retrogrademovement of the sector until member 25 vhas been rotated back in theopposite direction to bring depression 33 into such position that the 25roller can move into it.

from rod 31 and carry a pivot 40 lying substantially at right angles tothe arms. Rods 4| pass through aperatures in abutment 42 and areconnected to the arms 39 by means of externally 35 threaded sleeves 63which are retained on the rods by heads 44, loading springs 45 beingdisposed around the rods 4| between abutment 42 and heads 46 on the rodsto restrain piston 36- magnitude.

Movement 1nder 35 is limited by the arm 50 mounted on shaft 29 extendinginto the S101; 49 and a pin 5| named bysector 5,2 that 55 is pivotallymounted on guide 38 being disposed in the slot 48. The teeth 53 onsector 52 are engaged with a pinion 54 on shaft 55 to which is fixed thepinion 56 also, the latter pinion being meshed with a rack 51 connectedto piston valve 58 in the servo motor that controls immediately thestroke of the pump I4. Inasmuch as servo motors of this type are wellknown for the purpose herein mentioned and as the servo forms no part ofthe present invention, it will not be further described.

An auxiliary pump 59, driven by motor 68 which operates pump I4,supplies fluid under pressure through pipe 6I to actuate the servomotor, any excess of fluid being passed through relief valve 62 to atank 63 connected to pump 59 by return pipe 64.

Rudder post 9 actuates differential I9 through follow-up mechanismcomprising pinions S5, 66, shaft 61, pinions 68, 69 and shaft 18 towhich is xed arm 95. Upon an extension of shaft 61 is a pinion 1I meshedwith pinion 12 that is secured on shaft 13 to which is iixed a rudderangle index 14 movable over an angle scale 15. The wheel angle is shownon the same scale by index 16 on gear wheel 11 that is meshed with gear18 on shaft 22. The index 16 is disposed to contact adjustable stops 19to prevent further rotation of wheel I1 when the wheel has been moved toa position that will put the rudder hard over, the springs 88 on thestops serving to augment the eiiert required to turn the wheel and towarn the helmsman that the hard-over position is being approached. It isto be understood that gear 11 is not connected to shaft 13, but actsindependently of the shaft.

When wheel I'I is turned, the diierential I9 is acted upon and, sincethe rudder post and follow-up hold the planet pinions 23 and 24stationary, the member 25 is compelled to rotate, which swings thesector 28, rotates shaft 29 and, by means of arm 58, swings lever 81 onits pivot. This movement of lever 41 constrains sector 52 to rotate onits pivot and through the teeth 53, gear 54, shaft 55, gear 56 and rack51 the pump I4 is put on stroke and caused to begin to deliver i'luid toone or the other of the cylinders I2 and I3. As soon as ram II begins toslide, the follow-up mechanism acts through differential I9 upon sector28 to swing lever 81 and take stroke off the pump. However, the sector28 will not be moved until member 25 has been turned suiiiciently so toposition the depression 33 that roller 32 may move thereinto andsirnultaneously to engage teeth 21 with teeth 38. It is thus apparentthat full stroke is kept on the pump until substantially the end ofmovement of the rudder and, likewise, that while a relatively smallrotation of wheel I1 suices to put the pump on iullstroke, nevertheless,continued turning of wheel I1 in no way aects the operation of the pumpexcept to define the extent of operation of the follow-up necessary totake the stroke off the pump. Since shifting the position of pivot 48varies the relative length of the lever arms cooperating with sectors 28and 52, respectively, that position may be changed to increase thestroke put on the pump by a given degree of actuation of wheel I1 tocompensate for leakage due to wear of the pump parts.

, It will be observed that when the pressure rises to the point that theresistance of springs 45 is overcome, the piston 36 is moved outwardly,the fulcrum 40 of lever 41 is moved4 away from the center of rotation ofarm 58, thereby changing the lever arm between iulcrum 48 and arm 58 andalso 48 and pin 5I, whereby the effect upon the pump stroke of any givenangular extent will be made dependent upon pres ure conditions in the 5system. If arm 58 remains in fixed position while the fulcrum shifts,the lever 41 is rotated to change the setting of control spindle 55,thus varying the stroke of the pump to alter the rate 10 tially at themaximum pressure permitted by springs 45. It is obvious that there willbe no shifting of the fulcrum except when the pressure is in thevicinity of the predetermined maximum. The form of my invention shown inFig. 4 is 15 the same as that above described except for diferences inmechanism employed to transmit movement from sector 28 to controlspindle 55' and for omission of a torque equalizer from Fig. 4. Theshaft 8l upon which sector -28 is carried 20 serves no purpose otherthan supporting that Extending upwardly from sector 28 is a pin 82having one end disposed in a slot 83 in y lever 84 having a second slot85 in its other end.

A slidably mounted rod 86 has both ends down- 25 turned, the one of thembeing disposed in slot 85 and the other being disposed in a slot 81 inan arm 88 fixed to control spindle 96. Lever 84 is pivotally carried bya bracket 88 having in it elongated holes 89 through which securingmeans 30 are passed to nx the bracket to a support, the purpose ofelongating the holes being to make provision for shifting the bracket inthe direction of the length of lever 84 whereby the effective arms ofthe lever on opposite sides of its 35 pivot may be changed to vary thedegree of actuation of control spindle 55 for any given movement ofsector 28 and so to compensate for wear in the pump.

Fig. 5 shows in detail a device for transmitting 40 movement from sector28 to arm 88 on ,control spindle 55' which eliminates the sliding rod 86shown in Fig. 4 by having lever 84 act directly upon a pin 98 secured toarm 88. It is obvious that the sliding rod 86 in Fig. 4 can be connected45 directly to the piston valve of the servo motor shown in Fig. 1 orconnected immediately to the pump elements whereby the stroke ischanged.

The invention herein described may be manufactured-and used by or forthe Government of 50 the United States of Americay for'governmentalpurposes without the .payment of any'royalties thereon.

I claim:

1. The combination with hydraulic mechanism 55 that includes a pumphaving means to control the delivery of iiuid thereby, means driven bysuch delivered uid, a diierential gear device having two input elementsand an output element, a follow-up connecting said driven means G0 andone of said input elements, and manual operating means connected to theother input element, of means connecting said output element to saidcontrol means comprising' a cylinder, means placing said cylinder alwaysin communi- 65 cation with the pressure side of said plunger operable insaid cylinder, a guide for the outer end of said plunger, an abutmentmember adjacent that end of s'aid cylinder into which said plungerpasses, a lever pivotally mounted 70 on said plunger intermediate theends of said lever, means slidably engaged with the lever connecting anend of said lever to .the output element of the differential wherebylimited swing may be imparted to said lever by operation of saiddifferential, means slidably engaged with the lever connecting the otherend of said lever to the said control means, headed spring supportingrods slidable in said abutment, a loading 5 spring on each of said rodsbetween the head thereof and said abutment to restrain outward movementof said plunger, and adjustable means connecting said rods to theplunger to vary the position of the pivot of said lever when the forcein said cylinder acting on said plunger is less than the force exertedthereon by said springs.

2. The combination with hydraulic mechanism that includes a pump havingmeans to control the delivery of fluid thereby, means driven by suchdelivered fluid, a differential gear device having two input elementsand an output element,

a follow-up connecting said one of said input elements, and manualoperating means connected to the other input element,

of means connecting said output element to said control means comprisinga cylinder, means placing said cylinder always in communication with thepressure side oi said pum a plunger operable in said cylinder, a guidefor the outer end of said plunger, an abutment member adjacent that endof said cylinder into which said plunger passes, a lever pivotallymounted on said plunger intermediate the ends oi' said lever, meansslidably engaged with the lever of said lever to the output meansslidably engaged with the lever connecting the other end of said leverto said control means,

headed spring supporting rods slidable in said abutment, a laterallyextending arm fixed to each side of said plunger, a sleeve on each ofsaid rods adjustably engaged with said arm adjacent thereto and having aface adapted to contact said abutment tov limit the movement of saidplunger into said cylinder, and a loading spring on each of said rodsbetween a head thereof and said abutment to restrain outward movement ofsaid plunger.

3. The combination with hydraulic mechanism that includes a pump havingmeans to control the delivery of uid thereby, means driven by suchdelivered iluid, a diierential gear device having two input elements andan output element, a follow-up connecting said driven means is pivotallymounted, said bracket being adjustable longitudinally of the lever onthe bracket support,

lever and to said control means.

4. 'I'he combination with hydraulic mechanism that includes a pumphaving means to control the delivery of fluid thereb means driven by 5such delivered uid, a diierential gear device having two input elementsand an output element, a follow-up connecting said driven means and oneof said input elements, and manual operating means connected to theother input element, of a lever, a bracket on which said lever ispivotally mounted, said bracket being adjustable longitudinally of thelever on the bracket support, means slidably engaged with the leverconnecting one end of said lever to'said output element wherebyactuation of the output element driven means and imparts limited swingto said lever, and means slidably engaged with the lever connecting theother end of said lever to said control means.

5. 'I'he combination with hydraulic mechanism that includes a pumphaving means to control 5 the delivery of iiuid thereby, means driven bysuch delivered iiuid, a diiierential gear device having two inputelements and an output element, a follow-up connecting said -drivenmeans and one of said input elements, and manual op- 10 erating meansconnected to the other input element, of means connecting saiddiierential to said control means including a torque equalizer having acylinder connected to receive iluid under pressure from said pump and aplunger slid- 15 able in said cylinder, a lever pivotally mounted swingto said lever, means slidably engaged with the lever connecting theother end of said lever to said control means, and adjustable means tovary the limit of movement of said plunger into said cylinder. f

6. The combination with hydraulic mechanism that includes a pump havingmeans to control the delivery of fluid thereby, means driven by suchdelivered fluid, a differential gear device having two input elementsand an output ele- 30 ment, a follow-up connecting said driven means andone of said input elements, and manual operating means connected to theother input element, of means connecting said differential to saidcontrol means comprising a lever pivotally 35 mounted intermediate itsends, means slidably engaged with the lever connecting one end of saidlever to said output element whereby actuation of the diierentialimparts a limited swing to said lever, means slidably engaged with the40 lever connecting the other end of the lever to said control means,and adjustable means to vary semi-permanently the position of the pivotof the lever with respect to both of said connecting means independentlyof the action of any 45 other parts of the mechanism.

7. The combination with hydraulic mechanism that includes a pump havingmeans to control the delivery of iluid thereby, means driven by suchdelivered iluid, a diierential gear device having two input elements andan output element, a follow-up connecting said driven means and one ofsaid input elements, and manual operating means connected to theotherinput ele- 55 ment, of means connecting said output element to saidcontrol meanscomprising means responsive to pressure in said pump abovea predetermined magnitude, means to restrain responsive movement of saidpressure responsive means unytil said pressure reaches said magnitude, alever pivotally mounted intermediate its ends on an element of saidresponsive means to be moved translationally therewith, means slidablyengaged with the lever connecting one end of said lever 5 to said outputelement whereby there is imparted to the lever a limited swingingmovement when the differential is actuated, means slidably engaged withthe lever connecting the other end of 7o said lever to said controlmeans and means adl justable -to vary the position of the pivot of saidlever with respect to a xed element of said pressure responsive means.

RALPH* ERLING.

